Baling press

ABSTRACT

A baling press, comprising two substantially parallel press plates (1, 2) and at least four substantially parallel hydraulic pull cylinders (4, 5, 6, 7) which have been disposed to connect the press plates (1, 2) with each other and to pull them against each other.

BACKGROUND OF THE INVENTION

The present invention concerns a baling press comprising twosubstantially parallel press plates and a force means for pressing thesepress plates against each other. In particular, the invention concernsfast and high-capacity baling presses to be used in baling cellulose.

Cellulose baling presses in present use are mainly based on one specificconstruction principle. The press comprises a horizontal, lower pressplate which is stationary in relation to the base and an upper bracingplate fixedly attached thereto, above it, with the aid of posts oranother joining structure. Between the bracing plates has been disposeda, likewise horizontal, movable press plate, which has been providedwith a powerful hydraulic cylinder, braced against the bracing plate,for moving it in relation to the lower press plate and pressing itthereagainst, supported by guides or equivalent. Presses of this kindare intended in the first place for 200-kg bales, and the pressing forceof the presses is on the order of 1000 tons.

In the press just described, concentration of the resistance to pressingconstitutes a drawback. If the resistance to pressing, i.e., the balewhich is being pressed is not constantly positioned in the center of thepress, the centrally disposed hydraulic cylinder gives rise to aneccentric moment, which may cause breakage of the press. It should benoted that in practice the resistance to pressing may deviate fromcentered position even by several tens of centimetres; the consequencehas in fact been instances in which the press was broken.

When the production rate in a cellulose mill exceeds 1000 tons per day,it becomes necessary to press one bale more frequently than every 20seconds. This has necessitated dividing the production between twoseparate pressing and baling lines. The normal consumption of balingwire in a larger cellulose mill like this involves costs even in theneighbourhood of FIM 8000 per day, or FIM 3 million annually. To thismust be added the costs for wire required in tying up large units whenseveral bales are combined to make large units e.g. of 1600 kg each.

Furthermore, the 200-kg bales produced with existing baling presses areunsatisfactory because the baling wires running crosswise have to bemanually removed in the paper mill. The bales are moreover of differentsizes, and even otherwise defective, that is: there are internal gaps inthe large-size unit, which cause soiling and a risk of baledisintgration and toppling.

Baling presses in present use are unable to press bales larger thanthose containing 200 kg. In endeavours to develop bigger and moreefficient presses for larger bales and for increased pressing force,difficulties of structural designing have been encountered. However,press constructions of prior art are not applicable in higher capacitypresses: the structure simply fails in lack of strength.

Developing higher capacity baling presses is desirable in order toeliminate the drawbacks that have been mentioned and also in order toreduce the transport costs. Cellulose transporting costs, e.g. on theorder of FIM 160 to 280 per ton, are essentially directly proportionalto the bale volume. Thus for instance increasing the efficiency ofpressing by 10% would result in a corresponding reduction of transportcosts.

SUMMARY OF THE INVENTION

The object of the present invention is to eliminate the drawbacks setforth in the foregoing. In particular, the object of the invention is toprovide a new type of baling press design which can be applied in moreefficient presses, particularly for producing larger bales.

It is furthermore an object of the invention to provide a new type ofbaling press in which symmetric placement of the bale in the center ofthe press is not critical.

It is furthermore an object of the invention to provide a new type ofbaling press in the use of which the consumption of baling wire issignificantly less than before.

It is furthermore an object of the invention to provide a baling pressby using which the bales can be made uniform and mainly faultless, andconsiderably bigger than previous bales.

It is furthermore an object of the invention to provide a baling pressby using which the cellulose bale can be pressed to significantlysmaller volume than before so that the bale handling and freight costsare reduced.

It is furthermore an object of the invention to provide a baling presswhich is simpler of its construction than presses of prior art and morereliable in service than these.

Regarding the characteristic features of the invention reference is madeto the Claims.

The invention is based on a baling press design wherein twosubstantially parallel press plates have been joined with each other bythe aid of at least four, subastantially parallel, hydraulic pullcylinders so that the plates can be pressed against each other with theaid of said cylinders.

The press plates have then been appropriately disposed one above theother, substantially horizontally, and they constitute the upper andlower press plates. The upper press plate is then appropriatelysupported with the aid of supporting legs only, and the lower plate hasbeen suspended from the upper plate by meditation of the pull cylinders.Pressing will then take place with the aid of said pull cylinders; thepress opens, i.e., the lower plate descends by effect of its weight whenthe pressure in the cylinders is released.

In an alternative embodiment the lower press plate may, is desired, besupported on the base with the aid of supporting legs, in which casepressing takes place in the manner just described, by mediation of thepull cylinders. Then, however, the upper plate has to be provided with alifting means for opening the press. The lifting means may consist of ahydraulic lifting means, or the pull cylinders of the press, that is thepower cylinders, may be designed to be double-acting for moving theplates away from each other with the aid of the cylinders.

For centering the pressing force, and for avoidance of asymmetric loadson the pull cylinders, these cylinders may be attached to one of the twopress plates, or advantageously to both press plates, with the aid ofball joints. Further, for avoidance of torsion, the pull cylinders areadvantageously synchronized, e.g. hydraulically or in another way.Furthermore, the pull cylinders, e.g. 4, 6, 8 or several cylinders, areadvantageously placed symmetrically around the pressing areas of thepress plates, e.g. in square or rectangular configuration as viewed in asection perpendicular to the cylinders.

The baling press of the invention can be manufactured to have a pressingforce of such magnitude and with such capacity as is desired, byemploying a number of press cylinders consistent with the desiredpressing force.

By virtue of th present invention, stresses caused by torsion areavoided in the press, that is, the press that has been developed isappropriate to be used even in the event of asymmetric load, i.e., whenthe bale that has to be pressed assumes a position which is asymmetricin relation to the power cylinders, because during the pressing motionin the press only tension stresses acting on the cylinders and bendingstresses acting on the plates are produced. The deformations caused bythese stresses, and other detriments, are easily counteracted by meansof adequate strengths and material thicknesses. Hereby the press isappropriate to be constructed to press e.g. a twofold, fourfold,eightfold or even bigger bale, compared with the present 200-kg bale.The baling capacity will then increase substantially since a bigger baledoes not necessarily imply longer pressing time than a smaller bale. Onthe other hand, it is possible to lengthen the pressing time as thecapacity of the press increases, without incurring any problems on thebaling and packaging lines, whereby the bale can be compressed tosmaller volume, which is conducive to substantial reduction of packagingand transport costs.

The increased baling capacity achieved with the press of the inventionobviates the need of a parallel packaging line, even in a larger pulpmill, whereby space economy is achieved. Moreover, handling thecellulose in larger bales, and tying the bales up in larger units as arule, contributes substantially to reduced space requirements.Furthermore, the consumption of baling wire is substiantially reduced,compared with previous conditions. The bales will also be uniform and,owing to the increased pressing force, faultless in shape, whereby thebales will hold together without breaking up and they will not entailany risk of toppling.

Briefly observed, the baling press of the invention affords significantsavings with regards to bale pressing, bale tying, handling andtransport. The baling press of the invention is furthermore simpler inconstruction and more reliable in use than presses of prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in detail in the following with the aid ofembodiment examples, referring to the attached drawings, wherein:

FIG. 1 presents, viewed from obliquely above, a baling press accordingto the invention,

FIG. 2 presents another baling press according to the invention, partlysectioned and viewed from one end, its supporting legs removed,

FIG. 3 shows the section along line III--III in FIG. 2, and

FIG. 4 presents schematically, in elevational view, a third baling pressaccording to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 1 is seen a baling press, comprising two substantially parallelpress plates 1, 2 and a force means 3 for pressing said press platesagainst each other. As taught by the invention, the force means 3comprises at least four, in the embodiment here depicted six,substantially parallel hydraulic pull cylinders 4, 5, 6, 7, 18, 19,which have been arranged to connect the press plates with each other andto pull them against each other.

In the embodiment depicted, the press plates 1, 2 have been disposedhorizontally one above the other, and they constitute the upper pressplate 1 and the lower press plate 2. The upper press plate 1 issupported on the base 23 with the aid of four supporting legs 8. Thelower press plate 2 is suspended from the upper press plate 1 by meansof the pull cylinders 4, 5, 6, 7, 18, 19. The pull cylinders have beenplaced in rectangular configuration in relation to the press plates sothat between the cylinders is left a substantilly rectangularly shapedfree pressing zone 11. The press plates 1, 2 are not attached to eachother in any way other than by said pull cylinders, i.e., the pressplates are free of other mutual connections

When the baling press of FIG. 1 begins operation, the pressure isremoved from the cylinders 4, 5, 6, 7, 18, 19 (in order to betterillustrate the design, the hydraulic tubing has not been depicted),whereby the mass of the lower press plate 2 causes this press plate todescend into the lower position, shown in the figure. The cellulosesheets to be compressed, 12, (indicated with dotted lines in the form ofa bale) are thereafter transported onto the lower press plate 2 e.g.with the aid of conventional transporting means (in order to betterillustrate the design, not depicted). Next, hydraulic pressure isconducted into the force means 3, that is the said pull cylinders 4, 5,6, 7, 18, 19, whereby the pull cylinders, that is their piston rods 20,pull the plates against each other, thus pressing the bale between theplates. After desired pressing time, the pressure is released from thecylinders, whereby the lower plate 2 descends into the position of FIG.1, and the bale is removed and tied up. The pressing time may be e.g. onthe order of 10-30 seconds, or longer if desired, e.g. on the order ofone or several minutes.

In FIGS. 2-3 is seen another baling press according to the invention,comprising a force means 3, that is four pull cylinders 4, 5, 6, 7,which connected the horizontal, parallel press plates 1, 2 with eachother and which have been disposed to pull these plates against eachother. In FIG. 2, the supporting legs attaching the upper press plate 1to the base (not depicted) have been left out for greater perspicuity ofthe presentation.

In FIG. 2 is shown, partly sectioned, the attachment of the cylinder 4to the press plates 1, 2 with the aid of ball joints 10. In theembodiment here depicted, the piston 20 of the cylinder 4 pierces thepress plates 1, 2 through passages widening from the ball joints to thepressing surface of the press plate. The outer, that is lower, end ofthe piston 20 constitutes a spherical supporting surface 22 and it restsagaints a spherical supporting surface 21 provided on the lower plate 2.The part of the cylinder 4 adjacent to the piston likewise forms aspherical supporting surfaces 22, which is carried against the sphericalsupporting surfaces 21 provided on the upper press plate. The sphericalsurfaces on piston and cylinder and the respective spherical surfaces onthe press plates form ball joints, which permit turning on the cylinderin a direction parallel to the plane of the supporting plates.

FIG. 3 shows a section of the press. The piston rods 30 of the cylinder4, 5, 6, 7 have been placed in rectangular configuration, i.e.,symmetrically in relation to the press plate 2. Between the cylinders isleft a rectangularly shaped pressing zone 11 for bale pressing.

In FIG. 4 is shematically represented a press equivalent in principle tothe presses depicted in FIGS. 1-3, in this press however the lower pressplate 2 rest on the base with the aid of supporting legs 8. Moreover,the press comprises a lifting means for raising the upper press plate 1in relation to the lower plate. In the embodiment here depicted, saidlifting means consists of cylinder 4, 5, 6, 7, these cylinders havingbeen made double-acting so that the upper press plate can be lifted withthe aid of the cylinders in relation to the lower plate.

The embodiment examples are only meant to illustarate invention, andembodiments of the invention may vary within the scope of the claimsstated below.

I claim:
 1. A baling press for baling pulp, comprising:two substantiallyparallel press plates, having an upper press plate supported onsupporting legs disposed above a lower press plate in a substantiallyparallel plane; force means for pressing said press plates against eachother, said force means having at least four substantially parallel pullcylinders which have been disposed to connect said press plates witheach other and to pull said press plates against each other, wherein thepress plates are attached to each other by said pull cylinders so thatthe lower press plate is suspended from the upper press plate bymediation of said pull cylinders, and wherein said pull cylinders areconnected to both press plates with ball joints, wherein piston rods ofsaid pull cylinders extend through passages in said press plates to saidball joints and wherein said passages in said press plates widen fromthe ball joints to a pressing surface of the press plates to providelateral movement of said piston rods relative to said press plates toavoid torsion and binding in said press.
 2. A baling press according toclaim 1, whereby said press can accommodate pulp of varying density withless tendency for binding of said press.